Devesh, 

JNU started its btech programme last year where as IIIT Lucknow was established in 2015.

The curriculum of IIIT Lucknow is same as IIIT HYDERABAD and is more industry orientated so it will help you get a good package. 

No one can predict the placement of JNU. Whereas last year packages of IIIT Lucknow is very good. Avg package was 11.37 lacs and highest 28 lacs and it is expected to increase in coming years. 

In my view IIIT Lucknow is better. 

The rest depends on you.